[5.x] Fix term reference updates after slug change (#11058)

Author: daun

src/Http/Controllers/CP/Taxonomies/TermsController.php

@@ -168,6 +168,8 @@ public function update(Request $request, $taxonomy, $term, $site)
 
         $term = $term->fromWorkingCopy();
 
+        $term->term()->syncOriginal();
+
         $fields = $term->blueprint()->fields()->addValues($request->except('id'));
 
         $fields->validate([